The textile industry is probably the oldest industry in the world and is probably one of the largest of all of the established industries. Originally built primarily on the natural fibers, wool and cotton, the industry has evolved to one which includes cotton and wool, and synthetic textiles, and blends of the synthetics with wool and cotton. The most synthetic fibers used today include polyester, rayon and nylon (and other Aramids), along with a few specialized synthetic fibers, such as those manufactured basically from vinylidene chloride; modified cellulosic fiber such as cellulose acetate and cellulose triacetate; acrylic fibers modacrylic fibers; olefin fibers such as polyethylene and polypropylene; vinyon; vinal; azlon: nytril and novoloid, rayon and polyester having been developed during the advent of World War I, and the major development of Nylon taking place just prior to and during World War II. Polyester is the most heavily utilized man-made fiber in the world today.
The synthetic fibers which are used to create the synthetic textiles, do not have all of the properties desired by man and so there has been an excessive number of methods generated to alter the fibers and/or the textiles to enhance such desired properties. Zeronian and Collins, in an article entitled "Improving the Comfort of Polyester Fabrics", S. Haig Zeronian and Martha J. Collins, American Association of Textile Chemists and Colorists Book of Papers, 1987 International Conference and Exhibition, Oct. 14-16 1987, Charlotte Convention Center, Charlotte, NC, state that the strength, abrasion resistance, resiliency, and dimensional stability are considered to be satisfactory for most end uses of polyester. "However, polyester does have deficiencies in that it is hydrophobic and oleophilic. Polyester will build up static charge and oily stains on polyester are very difficult to remove." Zeronian et al, referencing Latta, B. M. "Clothing Comfort: Interaction of Thermal Ventilation. Construction and Assessment Factors. Eds. Hollies, N. R. S. and Goldman, R. F. Ann Arbor Science, Ann Arbor, Mich., 1977, pps 33-53, state that "There is the perception, also, that polyester fabrics are not as comfortable as natural fiber fabrics. In 1977, Latta stated that the comments of consumers suggested that the principal limitations of synthetics are unnatural hand, unpleasant thermal sensation, clamminess of fabric in contact with skin, lack of moisture absorbency, unfamiliar skin contact sensations and static-related problems. Much research and development work has been done over the years to improve the properties which have been thought to be inadequate."
Zeronian and Collins then proceed to discuss the techniques that can be undertaken to improve apparel comfort, stating, "Apparel comfort can be improved by a variety of techniques including apparel design fabric construction, yarn construction, fiber modification, blending fibers of different generic classes and topical finishing. The fiber modification can be accomplished either chemically and/or by engineering to change for example, the fiber cross section." Zeronian et al reference the following U.S. Pat. Nos.: Bauer, J. U.S. Pat. No. 4,370,143, issued Jan. 25, 1983; Nischwitz, E. et al, U.S. Pat. No. 4,136,218, issued on Jan. 23, 1979; Tripp, J. U.S. Pat. No. 4,352,917, issued Oct. 5, 1982; Stockburger, G. J. U.S. Pat. No. 4,427,557, issued Jan. 24, 1984; Totten, G. E. and Sabia, A. J. U.S. Pat. No. 4,463,036, issued July 31, 1984; Gillbers-LaForce G. E. and DeMartino, R. N., U.S. Pat. No. 4,569,974, issued Feb. 11, 1986; Hall, J. D. H., Ridge, B. P. and Whinfield, J. R. U.S. Pat. No. 2,590,402, issued Mar. 25, 1952, and Gajjar, N. J. U.S. Pat. No. 2,828,528, issued Apr. 1, 1958.
The U.S. Patent to Hall deals with the treatment of polyester with caustic to get lightweight polyester. It is now known that the caustic in that process literally chemically attacked the polyester and destroyed the polymer structure to give the weight loss.
The Gajjar patent deals with a special process to obtain low weight polyester fabrics, namely a calendering step at 100 degrees F. to 450 degrees F. under pressure, then a dry heat step at 250 degrees F. to 450 degrees F., then a caustic hydrolysis and drying to give the low weight fabric.
The Nischwitz process uses resinous binders to fix highly absorbing cellulose ethers on to the surface of the fibrous materials.
The Totten patent also describes a topical application using a hydrophillic copolymer and using an acid catalyst to enhance the fixation of the polymer to the surface of the fibrous material.
The Gillberg-LaForce patent deals with a process for the surface modification of polyester using an oligomer having a plurality of ester linkages in its molecule which are intended to attach to the surface of the fiber polymer.
Another topical application to fabric is the process described in the Stockburger patent, wherein anionic copolymers of ethylene glycol, polyethylene glycol, aromatic dicarboxylic acid and alkali metal salts of a sulphonated aromatic dicarboxyllic acid are used to improve soil resistance and improve water wicking of the fabric.
Yet another similar application is that found in the Tripp patent, wherein silylated organic polymers are used on polyester to impart hydrophillic properties to the treated fabric.
Finally, the most pertinent of the patents is the '143 patent issued to Bauer, in which there is disclosed a process for imparting improved moisture wicking, soil release and decreased static cling, which consists of immersing polyester fabric in an alkaline bath, adjusting the pH of the bath to 5.5 or less using acetic acid, and then adding a hydrophillic polyester polymer. Example 1 also describes the addition of trichlorobenzene after the adjustment of the pH to the acid side. Also, Examples 2 and 3 describe dye carriers but they do not describe the use of such carriers with the caustic treatment, an essential part of the instant invention.
A second area of the prior art is the preparation, dyeing, and finishing processes that are currently used in the textile industry. It is necessary to incorporate that background in this specification in order for those skilled in the art to have a full appreciation for the instant invention. Thus, fabric preparation includes wetting out of the fabric, scouring to remove natural waxes or spin finishes on the substrate, desizing to remove sizing from woven and warp knitted fabric, and bleaching to remove color from and to brighten the fabric. In dealing with this part of the textile process, Needles H. L., "Textile Fibers, Dyes, Finishes, and Processes", Noyes Publication, Park Ridge, NJ 1986, pps 154-157 discusses the requirements for preparation and drying of the textile in readiness for the final finishes. On reading Needles, one quickly observes that "Drying processes are currently under intense examination, since they account for nearly two thirds of the energy consumed in textile wet processing." Needles then goes on to discuss the "wet out" using surfactants; the scouring processes to remove oil and waxes, including the scouring of textiles using caustic; desizing using dilute acids or enzyme treatments and short washing techniques; drying by the use of squeeze rolls or by passing the fabric over narrow slits from which sonic velocity steam blows water from the fabric or draws water from the fabric by vacuum, and, the final step of removing remaining water by convection, conduction or radiation heating.
A third area of the prior art that has been briefly discussed in the Bauer patent supra, that is of importance to the instant invention is the area of disperse dye carriers used in polyester dyeing. Here, too, Needles has discussed the current state of the art regarding the dyeing of polyesters. Thus, at page 184 he discusses various specialized techniques for application of disperse dyes to polyesters. The importance of the disclosure on that page is not the dyeing process itself, but the fundamental understanding of the part that disperse dye carriers play in the process of dyeing polyesters. That discussion is being incorporated herein, in part, as an understanding of the mode of action of the disperse dye carriers in polyester dyeing. Thus, he discloses that the carriers penetrate the polyester, open up the molecular structure of the fiber (often resulting in swelling of the fiber), and aid in passage of the disperse dye across the dye solution-fiber interface and within the fiber. Needles also discusses the need for elevated temperatures, and high pressures in some cases, along with the disperse dye carriers, to effect the dyeing of the polyesters in a uniform manner. He notes that suitable carriers include aromatic hydrocarbons such as diphenyl and methylnaphthalene phenolics such as o-and p-phenylphenol, halogenated aromatics such as the di- and trichloro-benzenes, aromatic esters including methyl salicylate, butyl benzoate, and diethylphthalate, and benzaldehydes. Finally, Needles discusses "thermosol dyeing" in which polyester containing disperse dye applied to the fiber surface is heated near 200 degrees centrigrade under partial vacuum for a short period of time. Needles comments that "At this temperature, the molecular motion within the polyester is high, permitting the dye vapor to penetrate into the fiber. On cooling, the disperse dye is permanently trapped and fixed within the fiber. Finally, Needles sets forth the various industry accepted means by which the process can be carried out, namely, fiber/stock dyeing; yarn/skein dyeing; package dyeing; jig dyeing: beck dyeing: jet dyeing; range dyeing, beam dyeing, and foam dyeing.
In another pertinent article regarding the use of disperse dye carriers, "Some Observations on the Effects of Selected Dye Carriers on Poly(ethylene terephthalate)", Ravichandran, V. et al., Textile Chemist and Colorist, November, 1987, Vol. 19 No. 11, pg. 35, Ravichandran et al observed that the disperse dye carriers gave enhanced wicking and wettability to pretreated poly(ethylene terephthalate) fabrics, and that the increased wettability persisted even after the fabrics were stripped of the carrier by solvent extraction, concluding that the pretreatment gave some permanent change to the poly(ethylene terephthalate), speculating that the disperse dye carriers exert a dual role in modifying the PET surface and plasticizing the polymer bulk. Thus, one can observe that the process of moving a textile from the prefinish stage to the finished stage requires an extreme amount of handling and processing if the current art technologies are used.
The instant invention overcomes most of the problems associated with the prior art processes. Most notably, the instant invention process is fast, efficient, clean, inexpensive and is essentially a one-step scouring/desizing process for removing the materials used in the manufacture of the fiber and the materials used for subsequent treatment in the fabrication of the textile, from such textiles. These materials include substances such as oils, sizes, spin finishes, lubricants, knitting oils and graphite, just to name a few.
The instant invention enhances some of the functional properties of the treated textile, namely, with continuous polyester filament, the end product is totally lint free. The polyester end product retains its non-flammable characteristics; has an enhanced moisture regain property which is durable; retains it wrinkle free characteristics; is quick drying, hence leading to large energy savings; has enhanced soil release properties; has enhanced printability, and in some cases, the instant process creates printability on textiles; the instant invention process reduces Barre of the end product and the instant invention process enhances the water absorbency of the end product, even on those textiles that are considered to be hydrophobic, such as nylon and polyester and, the instant invention process is forgiving in the sense that it can be used on a variety of textiles and in a variety of equipment already being used by the textile industry, without any major modifications of the equipment being necessary.